Nutrition Management of the Very Low-birthweight Infant: II. Optimizing Enteral Nutrition and Postdischarge Nutrition

Abstract

After completing this article, readers should be able to: 1. List the protein requirements for extremely low-birthweight neonates. 2. Delineate the most desirable nutrition goal for the preterm infant. 3. Describe the potential adverse effects of inadequate nutrient intakes in very low-birthweight infants. 4. Explain the most appropriate diets and their benefits for preterm infants after hospital discharge. Optimizing enteral nutrition (Fig. 1) begins as feedings are advancing and addresses the recommendation from the American Academy of Pediatrics Committee on Nutrition that preterm infants be provided levels of nutrients to permit growth and composition of weight gain for a normal fetus of the same postconceptional age. Normal concentrations of blood and tissue nutrients also must be maintained. However, many days or weeks may be required to achieve recommended intakes, particularly for infants who have major morbidities or are of extremely low birthweight (Fig. 2). Figure 1. Aggressive nutrition to prevent extrauterine growth restriction. PWL=postnatal weight loss, RTBW=return to birthweight, TPN=total parenteral nutrition, D/C=discharge, IWL=insensible water loss, CAPS=baby hats, ICF=intracellular fluid, AA=amino acids, E/N=energy/nutrition, PTF=preterm formula, H.C.=head circumference. Reprinted with permission from Adamkin DH. J Perinatol. 2006;26(suppl 1):S27–S30. Figure 2. Mean body weight versus gestational age in weeks for all study infants who had gestational ages at birth of between 24 and 29 weeks. Reprinted with permission from Ehrenkrantz RA, et al. Pediatrics. 2006;117:1253–1261. The most commonly used method for estimating the protein intake necessary to maintain the intrauterine rate of protein accretion is the factorial method, which includes an estimate of inevitable urinary nitrogen losses (ie, the losses that occur in the absence of nitrogen intake) and an estimate of the amount deposited in utero corrected for efficiency of absorption and deposition. An alternative method is to determine the actual intakes that support intrauterine rates of growth and nitrogen accretion. Interestingly, the two approaches do not result …